Abstract: FRUIT PROTEASES: EFFECT ON GELATIN. Joanna Mendelsohn. The purpose of this lab was to explore the effects of proteolytic enzymes found in fruit upon gelatin. Kiwi was the source of the fruit proteases. The mass of Petri dishes, kiwi, and gelatin were measured. Gelatin and kiwi were incubated together for 24 hours, liquid and kiwi were removed, and then the mass of Petri dish and gelatin was determined. Protease effect was calculated as percent liquefied gelatin per gram of kiwi, where percent liquefied gelatin is the mass of liquefied gelatin divided by the initial mass of gelatin multiplied by 100. The effects of heating the kiwi and freezing the kiwi on proteolysis of gelatin were tested. Untreated kiwi had an average protease effect of 18.76%/g kiwi. Frozen kiwi had an average protease effect of 19.09%/g kiwi. Kiwi was heated at 2 minute intervals. Kiwi heated 2 minutes had an average range protease effect of 13.07-21.15%/g kiwi. Kiwi heated by 6 minutes had an average range protease effect of 4.480-9.710%/g kiwi. This shows that proteases in kiwi can liquefy gelatin. Freezing kiwi has no effect on the proteases, but heating kiwi for 6 minutes or more largely deactivates the proteases effect on gelatin.
Key words: Proteases, proteolytic enzymes, denaturation, gelatin
Results:
Each treatment was repeated in 3-4 Petri dishes and data taken during the lab can be found in data tables 1-5. Calculations were placed in a large table at the end of the report. The effect of untreated kiwi on gelatin was determined. Untreated kiwi had an average protease effect of 18.76% liquefied/g kiwi. To determine the effect of freezing on the protease effect of kiwi, kiwi was placed in a freezer for 24 hours and then allowed to return to room temperature. Freeze treated kiwi had an average protease effect of 19.09 % liquefied/ g kiwi. To determine the effect of heating on the protease effect of kiwi, kiwi was heated in a hot water bath in 2-minute increments up to 10 minutes. Kiwi heated for 2 minutes had an average protease effect of 17.11 % liquefied/ g kiwi. Kiwi heated for 4 minutes had an average protease effect of 11.11 % liquefied/ g kiwi. Kiwi heated for 6 minutes had an average protease effect of 7.092 % liquefied/ g kiwi. Kiwi heated for 8 minutes had an average protease effect of 6.970 % liquefied/ g kiwi. Kiwi heated for 10 minutes had an average protease effect of 5.150 % liquefied/ g kiwi. The repeated treatments had very similar results except for the 2 minute test and the 4 minute test which had some large deviation.
Data Table 1: Control Dishes-Day 1
Dish Number
Mass without Kiwi (g)
Mass with Kiwi (g)
Mass after Reaction (liquid gelatin poured off) (g)
1
11.14
12.16
10.23
2
11.50
12.67
10.25
3
11.07
12.12
10.38
Data Table 2: Heat Tests-Day 2
Time Heated
Dish Number
Mass without Kiwi (g)
Mass with Kiwi (g)
Mass after Reaction (liquid gelatin poured off)
(g)
6 minute
4
11.40
12.31
10.98
6 minute
5
10.98
12.08
10.51
4 minute
6
11.72
13.08
11.32
4 minute
7
10.71
11.34
10.10
2 minute
8
11.63
12.71
11.05
2 minute
9
10.85
11.69
11.30
Data Table 3: Freezing Tests-Day 3
Dish Number
Mass without Kiwi (g)
Mass with Kiwi (g)
Mass after Reaction (liquid gelatin poured off)
(g)
10
11.04
12.27
10.14
11
10.93
12.03
9.89
12
10.55
11.72
9.68
Data Table 4: Heat Tests-Day 4
Time Heated
Dish Number
Mass without Kiwi (g)
Mass with Kiwi (g)
Mass after Reaction (liquid gelatin poured off)
(g)
2 minute
13
10.46
11.47
10.01
2 minute
14
10.29
11.59
8.820
4 minute
15
10.59
11.64
10.31
4 minute
16
10.46
11.30
10.19
6 minute
17
10.95
12.19
10.74
6 minute
18
10.72
12.02
10.45
Data Table 5: Long Heat Test-Day 4
Time Heated
Dish Number
Mass without Kiwi (g)
Mass with Kiwi (g)
Mass after Reaction (liquid gelatin poured off)
(g)
8 minute
19
10.46
11.43
10.26
8 minute
20
10.76
11.69
10.52
8 minute
21
10.18
11.11
9.87
10 minute
22
10.88
11.98
10.66
10 minute
23
10.86
11.93
10.68
10 minute
24
10.63
11.58
10.37
Summary
In this lab, “Monitoring of Enzymatic Proteolysis Using Self-Assembled Quantum Dot-Protein Substrate Sensors”, protease interactions were monitored and tested. The results from this test were primarily found by using a hybrid semiconductor quantum dot peptide substrate that would monitor the enzymatic proteolysis. The digestive proteins that were monitored were cysteine protease papain and serine protease endoproteinase K. This lab also collected some data that explored things that inhibit these enzymes that cause protein digestion. This lab explained that papain is formed from peptide bonds and that it hydrolyzes esters and amides. Proteinase K can hydrolyze native and denatured proteins and it can also inactivate other enzymes. In the results portion of the lab some of the results were discussed and related to DNA and RNA in the human body. The basic goal of this lab was to explore protease interactions and then test them.
Clapp AR, Goldman ER, Uyeda HT, Chang EL, Whitley JL, Medintz IL. 2008.
Monitoring of enzymatic proteolysis using self-assembled quantum do-protein substrate sensors. J Sensors. Vol. 2008, Article ID 797436. Available from: http://www.hindawi.com/journals/js/2008. (Accessed 2010 Feb 6).
Abstract:
FRUIT PROTEASES: EFFECT ON GELATIN. Joanna Mendelsohn. The purpose of this lab was to explore the effects of proteolytic enzymes found in fruit upon gelatin. Kiwi was the source of the fruit proteases. The mass of Petri dishes, kiwi, and gelatin were measured. Gelatin and kiwi were incubated together for 24 hours, liquid and kiwi were removed, and then the mass of Petri dish and gelatin was determined. Protease effect was calculated as percent liquefied gelatin per gram of kiwi, where percent liquefied gelatin is the mass of liquefied gelatin divided by the initial mass of gelatin multiplied by 100. The effects of heating the kiwi and freezing the kiwi on proteolysis of gelatin were tested. Untreated kiwi had an average protease effect of 18.76%/g kiwi. Frozen kiwi had an average protease effect of 19.09%/g kiwi. Kiwi was heated at 2 minute intervals. Kiwi heated 2 minutes had an average range protease effect of 13.07-21.15%/g kiwi. Kiwi heated by 6 minutes had an average range protease effect of 4.480-9.710%/g kiwi. This shows that proteases in kiwi can liquefy gelatin. Freezing kiwi has no effect on the proteases, but heating kiwi for 6 minutes or more largely deactivates the proteases effect on gelatin.
Key words: Proteases, proteolytic enzymes, denaturation, gelatin
Results:
Each treatment was repeated in 3-4 Petri dishes and data taken during the lab can be found in data tables 1-5. Calculations were placed in a large table at the end of the report. The effect of untreated kiwi on gelatin was determined. Untreated kiwi had an average protease effect of 18.76% liquefied/g kiwi. To determine the effect of freezing on the protease effect of kiwi, kiwi was placed in a freezer for 24 hours and then allowed to return to room temperature. Freeze treated kiwi had an average protease effect of 19.09 % liquefied/ g kiwi. To determine the effect of heating on the protease effect of kiwi, kiwi was heated in a hot water bath in 2-minute increments up to 10 minutes. Kiwi heated for 2 minutes had an average protease effect of 17.11 % liquefied/ g kiwi. Kiwi heated for 4 minutes had an average protease effect of 11.11 % liquefied/ g kiwi. Kiwi heated for 6 minutes had an average protease effect of 7.092 % liquefied/ g kiwi. Kiwi heated for 8 minutes had an average protease effect of 6.970 % liquefied/ g kiwi. Kiwi heated for 10 minutes had an average protease effect of 5.150 % liquefied/ g kiwi. The repeated treatments had very similar results except for the 2 minute test and the 4 minute test which had some large deviation.
Data Table 1: Control Dishes-Day 1
Data Table 2: Heat Tests-Day 2
(g)
Data Table 3: Freezing Tests-Day 3
(g)
Data Table 4: Heat Tests-Day 4
(g)
(g)
In this lab, “Monitoring of Enzymatic Proteolysis Using Self-Assembled Quantum Dot-Protein Substrate Sensors”, protease interactions were monitored and tested. The results from this test were primarily found by using a hybrid semiconductor quantum dot peptide substrate that would monitor the enzymatic proteolysis. The digestive proteins that were monitored were cysteine protease papain and serine protease endoproteinase K. This lab also collected some data that explored things that inhibit these enzymes that cause protein digestion. This lab explained that papain is formed from peptide bonds and that it hydrolyzes esters and amides. Proteinase K can hydrolyze native and denatured proteins and it can also inactivate other enzymes. In the results portion of the lab some of the results were discussed and related to DNA and RNA in the human body. The basic goal of this lab was to explore protease interactions and then test them.
Clapp AR, Goldman ER, Uyeda HT, Chang EL, Whitley JL, Medintz IL. 2008.
Monitoring of enzymatic proteolysis using self-assembled quantum do-protein substrate sensors. J Sensors. Vol. 2008, Article ID 797436. Available from: http://www.hindawi.com/journals/js/2008. (Accessed 2010 Feb 6).